Billet handling device



Oct. 27, 1959 SB RN, J ETAL 2,910,565

BILLET HANDLING DEVICE Filed Aug. 16, 1956 INVENTORS I; HARRY a. OSBORNJR.

WI AM E. BENNINGHdFF United 2,910,565 BILLET HANDLING DEVICE Harry B.Osborn, Jr., University Heights, and William E. Benninghoff,Brecksville, Ohio, assignors to The Ohio Crankshaft Company, Cleveland,Ohio, a corporation of Ohio Application August 16, 1956, Serial No.604,435

Claims. (Cl. 21910.41)

The present invention pertains to the art of induction heating and, moreparticularly to apparatus for induction heating using polyphaseinduction heating coils.

In the art of induction heating, it is well known that induction heatingcoils energized from a polyphase alternating current source exert amagnetic force on the billet being heated which tends to move the billetlengthwise of, or axially out of the coil. Because of this, manyelaborate stops and means have been devised to prevent the billet frombeing forced out of the coil by the magnetic field established by thecoil. Attempts have also been made to neutralize the magnetic forcesestablished by the coil by having part of the coil establish magneticforces in a direction opposite those established by another part of thecoil. These various attempts in the past have provided means to keep thebillet in the coil but at the same time have added unnecessary structureto the equipment or have slightly changed the heating pattern in thebillet. For example, if stops were used to prevent the billet moving outof the coil while the coil was energized, it was necessary to remove thestops in order to take the billet out of the coil after it is heated.Such stops had to be provided with cooling systems and means for movingthem out of the Way.

The present invention contemplates an extremely simplified billetheating and handling device wherein no stops or other means outside ofthe heating coils are required to hold the billets within the coils.

In accordance with the invention, a pair of polyphase induction heatingcoils are arranged in a spaced endto-end relationship in such mannerthat the magnetic force exerted by the coils on the billets therein isin opposite directions so that each coil, operating through the billetcontained therein, holds the billet in the other coil while it isenergized.

Further, in accordance with the invention, the coils may be positionedon one or opposite sides of a common post heating or soaking chamber, orthe like, so that each billet in turn may be allowed to soak after ithas been heated by a coil. This soaking chamber may be provided with adoor in the side thereof and a track, or other suitable means, so thatthe billets may be easily removed therefrom. The billets may bealternately heated in the coils and then moved into the soaking chamherin a timed relationship wherein the billets in the coils receiveinducedheat therein simultaneously, with the billet in one coil reaching itsmaximum heating temperature or full heat, while the billet in anothercoil is in its initial heating stage. The coils are connectable throughsuitable contactors to a power source of induction heating energy toenergize them for heating of the billets by the induction heatingprocess.

Auxiliary controls and the turning on and oil of the power source to thecoils may be hand operated or automatically operated. It is understoodthat these controls may be operated in a timed relationship with eachother by means of a time clock device or other suitable means or thatthey may be operated in accordance with the temperature of the billetitself. When they are operated in accordance with the temperature of thebillet itself, suitable temperature responsive devices and tem peraturemeasuring devices would be associated with the induction heatingapparatus, or furnace, or billet heating apparatus illustrated anddescribed herein.

Therefore. one of the objects of the present invention is to provide aninduction heating furnace or apparatus which is novel in arrangement andis highly efiicient in operation, by eliminating down-time or waste timeduring the cycle of operation.

A further object of the invention is to provide an induction heatingapparatus in which induction heating coils are placed in end-to-endrelationship so that the magnetic force of one coil keeps a billet inthe other coil.

A still further object of the invention is to provide an inductionheating arrangement wherein billets may be longitudinally fedalternately from two heating coils into a common soaking chamber andthen ejected from the soaking chamber transversely to the longitudinalmovement.

Still a further object of the invention is to provide a novel method ofheating billets by using a pair of induction heating coils positioned inend to end relationship, and on opposite sides of a common soakingchamber; the method comprising the steps of simultaneously heating oneof the billets for the first half of its heating cycle in one coil andanother billet for the second half of its heating cycle in theothercoil, while a third billet is soaking in the soaking chamber,removing the billet from the soaking chamber and inserting the heatedbillet into the soaking chamber, placing an unheated billet inthe coilwhere the heated billet was and again energizing the coils so that thebillet which was previously heated during the first half cycle, is nowheated for the second half of its heating cycle and the newly addedbillet is heated for the first half of its heating cycle.

Further objects and other modifications of the invention relating to theart of heating billets and induction heating apparatus will become moreapparent from the following description of one of the preferredembodiments of the invention where taken in conjunction with theaccompanying drawings in which:

Figure 1 is a toppl'an view of the billet heating apparatus,

Figure 2 is a sectional view taken approximately along the line 2-2 ofFigure 1,

Figure 3 is a cross-sectional view taken approximately along the line 33of Figure 1,

Figure 4 is a sectional view similar to Figure 3 but with the door ofthe soaking chamber in open position and illustrating the removal of thebillet therefrom, and

Figure 5 is a top plan view partly in section of the modification of theinvention. i

The invention pertains to an induction heating apparatus for heatingbillets wherein the billet is heated by an induction heating coil andimmediately moved into a soaking chamber which is also heated so thatthe heat pattern throughout the cross section of the billet will becomeuniform. The invention also pertains to the novel arrangement ofinduction heating coils for heating billets wherein the heating coilsestablish magnetic fields of force opposing each other so that stops arenot required to hold the billets within the heating coil during theheating theerof.

The preferred embodiment of the invention and one of the ways in whichthe invention may take physical form is illustrated in Figure l. Theheating apparatus in Figure 1 comprises induction heating coils 10 and11 arranged in substantially coaxial longitudinal alignment or in end toend relationship and spaced apart by means of a soaking chamber 12 whichis positioned between the mean ends of the coils and 11. The inductionheating coils 10 and 11 are connectable to a source of power or, asillustrated, to respective sources of power 13 and 14 which are amultiphase or preferably a threephase source of alternating current insuch manner that the magnetic field of the coils oppose each other. Themagnetic field of the coil 10 exerts a force in the direction of thearrow 15 on a billet in that coil and the magnetic field of the coil 11exerts a force in the direction of the arrow 16 on a billet in thatcoil. The magnetic forces of both coils, as indicated by the arrows 15and Y 16, are directed towards the soaking chamber 12.

The soaking chamber 12 is provided with end openings and a side openingso that billets may be moved endwise from either coil into the soakingchamber and then moved in a side-ways direction therefrom. In otherwords, the billets are moved through the coils in the direction of thearrows 15 and 16, into the soaking chamber 12, and then are moved out ofthe soaking chamber 12 in a direction transverse to the direction of thearrows 15 and 16.

The coils 10 and 11 and the soaking chamber 12 may be provided with apair of skid rails 17 which extend longitudinally through the coils andthe soaking chamber. These skid rails 17 support the billets during theheating, post heating, or soaking periods of time and permit much easierhandling of the billets with less force required than if no skid railswere used. However, it is understood that other suitable means may beemployed in place of the skid rails, if desired. It has been founddesirable to provide a track 18 or other suitable means extendingtransversely to the skid rails 17 and outwardly from the soaking chamber12 and on which the billet moves when it is removed from the soakingchamber 12. Only one billet is shown in each coil and in the soakingchamber. Obviously more than one could be so located.

The soaking chamber 12 which is positioned between the mean or adjacentends of the induction heating coils 10 and 11, is best illustrated incross section Figures 3 and 4. The chamber may be formed of any suitablematerial such, for example, a heat insulation material constructed intoa unitary structure on the top 19, back 20 and bottom sides 21, andhaving a door 22 on the front side thereof. The door 22 is hinged at thetop edge thereof to the top 19 so that it may be opened when a billet isto be ejected or removed from the'soaking chamber. In Figure 3 a billetis illustrated on the rails 17 and in Figure 4 the billet is illustratedas having been moved from the rails 17 onto the track 18 and through theopened door by means of a piston 23 of an air cylinder 24 or the like.Door 22, in this instance, was opened by an air cylinder 25 mounted ontop of the chamber. However, it is understood that other suitable meansincluding manual opening of the door may be used in place of the aircylinder 25 if desired, and that other suitable means may be used inplace of the air cylinder 24 and piston 23 which move the billet fromthe rails 17 to the track 18. It is understood other suitable devices,such as motor driven means or solenoid motored devices may be used inplace of the air cylinders, if desired. The soaking chamber 12 may alsobe provided with auxiliary heating elements 26 if desired to keep thetemperature of the atmosphere or air immediately surrounding the billetsoaking therein at an elevated temperature. Such elements 26 may be gasburners or induction heating coils but are shown as resistance heatingcoils.

The billet handling device illustrated in Figures 1 to 4 inclusive,operates as follows: Assume that there is a billet A in coil 10, abillet B in coil 11, a billet C in the soaking chamber 12, a billet Dready to be inserted in the coil 10 and a billet E ready to be insertedin the coil 11. Also assume that the billet A. has been heated todesired or full temperature by the coil 10, that billet B has receivedpart of its heat so that it is heated partly to its full temperature bycoil 11 and that billet C has been fully heated and is soaking in thechamber 12 to obtain a uniform heat pattern throughout its crosssection. Also assume that at this particular instance, the power hasbeen shut off from the power sources 13 and 14 by suitable contactors orother similar means so that the induction heating coils 1t and 11 arede-energized.

With these assumptions forming a starting point, the first step in theoperation is to energize the air cylinder 24 and the air cylinder 25 toremove the billet C from the soaking chamber 12 or to move it from therail 17 onto the track 18 in a transverse direction relative to thecoils 10 and 11. After the billet C has been removed from the soakingchamber 12 and the air cylinders 24 and 25 tie-energized so that theyreturn to their normal position and the door 22 is closed, the coil 10is connected to the power source 13. Energization of the coil 10establishes a magnetic field forcing the billet A in the direction ofthe arrow 15 from the coil 10 and into the soaking chamber 12 until itbumps against the billet B in coil 11. This positions the billet A inthe soaking chamber. At the same time an air cylinder 27 mounted on theskid rails 17 may be powered to push billet D into the extreme end ofthe coil 10 and until the billet B abuts against billet A which is nowin the soaking chamber 12.

Next, the coil 11 is connected to the power source 14 so that it isenergized to continue the heating of the billet B. Both coils areenergized until the billet B reaches its full temperature and billet Dreaches partially towards its full temperature. Simultaneously, the heatpattern in the billet A, which is now in the soaking chamber, gains auniform heat pattern so that the center of the billet is at about thesame temperature as the outside of the billet. When the billet B hasreached its full temperature, both coils 10 and 11 are de-energized. The

billet A is then removed from the soaking chamber 12 by energizing aircylinder 24. The billet B is inserted into the soaking chamber 12 and anew billet E inserted into the coil 11 by energizing coil 11 and aircylinder 28. Coil 10 is next energized so that billet D will be heatedto full temperature while billet E is heated to partial temperature andbillet B soaks in chamber 12. This cycle of operation may be continuedon succeeding billets.

It is noted that while the coils 10 and 11 are energized, the magneticforce urges the billets therein towards the soaking chamber and againstthe billet which is in the soaking chamber. It is also noted that eachtime the power is turned on or both coils are energized, they beat thebillet contained therein partially towards its full heating temperature.Thus the billets in the coils 10 and 11 are alternately heated to theirfull heating temperature and then moved into the soaking chamber so thata billet in the soaking chamber remains there for a period of time equalto, or approximately equal to, a definite part of the total heatingcycle and a definite part of the time during which the billet is heatedby its respective coil. Generally, a billet remains in the soakingchamber a period of time equal to about one half of the length of timerequired to induce the heat into the billet while it is within theinduction heating coil.

A modification of the invention is illustrated in Figure 5. In thismodification, one of the induction heating coils has been eliminated.The modified structure includes a heating coil and a soaking chamber112, the induction heating coil 111) being connectable to a suitablesource of power 113. The soaking chamber 112 is con structed verysimilar to the soaking chamber 12 with the exception that the endfarthest from the end of the coil 110 is provided with a stop againstwhich the billet bumps when it is ejected from the coil 110 into thesoaking chamber 112.

In this modified device, a billet may be left in the soaking chamber thefull length of time that the coil 110 is energized to heat anotherbillet. In operation, the coil A is energized until the billet thereinbecomes heated. Then the power is turned 0133, or coil A de-energized. Apreviously heated billet in the chamber 112 is then pushed out sideways.Next, the coil 110 is again energized to move the billet therein endwiseinto the chamber 112 so that a new billet may be inserted in the coil.This entire cycle may be automatic by providing suitable current.

controls between the power source 113 and the coil and on the aircylinders which move the billet out of the soaking chamber 112. Thesecontrols may be integrally joined together and operated by a temperaturemeasuring device either positioned in the stop 130m engageable with a.billet at another desired location in the coil 110 or the soakingchamber. 112. When such mechanisms are used, the temperature responsivedevice would operate the controls when the billets were heated to theirdesired temperature so that each succeeding billet would be heateduniformly.

In both the main embodiment of the invention, as illustrated in Figures1 to 4 inclusive, and in the modification of Figure 5, it is noted thatthere are no stopswhich have to be moved out of the Way so that a billetmay be removed from the induction heating coil. In each instance thebillet has induced in it, in a relatively short period of time, the heatrequired to heat the billet by fire induction heating coil. Then thebillet is moved into the soaking chamber to allow the heat to obtain auniform heat pattern throughout the billet. In both instances, it isnoted that every coil exerts a magnetic force on the billet within it ina direction towards the soaking chamber. In the preferred embodiment ofthe invention, the forces inserted on the billets from the coils are inopposite directions and in both modifications of the invention it isnoted that the billets are removed from the soaking chamber in adirection transverse to their path of movement in an endwise directionthrough the induction heating coil.

It is understood that other details or modifications of the inventionmay be made without departing from the spirit and the scope of theinvention as hereinafter claimed.

Having thus described our invention, we claim:

1. A pair of induction heating coils in end-to-end rela "necting eachcoil to a multiphasee source of electric power.

2. A structure as defined in claim 1 wherein the induction heating coilsare connected so that their magnetic fields of force oppose each otherand urge billets in the coils toward said adjacent ends of the coils.

3. In a billet heating apparatus, a heating chamber, induction heatingcoils, one on either side of said chamber, means for moving billets intoextreme ends of said induction heating coils, said chamber havingopenings in the walls thereof for passing billets from the inductionheating coils into the heating chamber, said chamber having an openingin a wall thereof and provided with a closable door through whichbillets may be ejected from the heating chamber in a directiontransverse to the movement of the billets from the induction heatingcoils into the chamber, and means for connecting each coil to amultiphase source of power.

. having an opening therein aligned with the passageway of said coil,and having stop means abuttable by a billet moving from the heating coilto the soaking chamber to position the billet in the chamber, billetsupporting means extending through said coil into said chamber, andmeans for removing the billet from the chamber in a direction transverseof the direction of moving the billet through the induction heating coiland into the chamber.

6. The structure of claim 1 including rail means extending continuouslythrough said coils and track means extending from the adjacent ends ofsaid coils in a direction transverse to said rail means.

7. The structure of claim 3 including rail means extending continuouslythrough said coils and said chamber and track means extending from saidchamber in a direction transverse to said rail means.

8. Method of heating billets by means of a pair of induction heatingcoils and a soaking chamber positioned therebetween, said methodcomprising the steps of heating a first billet the second part of abillet heating period in one coil, and simultaneously heating a secondbillet the first part of a heating period in the other coil, placing thefirst billet in the soaking chamber and a third billet in the inductionheating coil for heating, heating the second billet the second part ofits heating period and the third billet the first part of its heatingperiod while the first billet remains in the soaking chamber, removingthe first billet from the soaking chamber and placing the second billetin the soaking chamber, placing a fourth billet in the heating coil justpreviously heating the second billet and repeating the operation onsucceeding billets. v g

9. The method as defined in claim 8 wherein the first part of theheating period and the second part of the heating period are equal intime length.

10. The method of heating billets using two induction heating coils anda common post heating soaking chamber positioned between the adjacentends of the coils, said method comprising the steps of energizing theheating coils simultaneously to simultaneously partially heat thebillets in both coils in such manner that one billet is heated to itsfull heating temperature prior to the heating of the other billet to itsfull heating temperature, and alernately removing the billets from theheating coils into the soaking chamber as they are heated and leavingeach billet in the soaking chamber until another billet has been heatedto its full heating temperature.

References Cited in the file of this patent UNITED STATES PATENTS2,325,638 Strickland Aug. 3, 1943 2,454,039 Cox Nov. 16, 1948 2,604,577Strickland et al July 22, 1952 2,669,647 Segsworth Feb. 16, 1954

